The overall objectives of our research are two-fold: a) to elucidate the mechanism of action of insulin and proinusulin on various isolated cells from insulin-sensitive and insensitive tissues by studying the metabolic parameters of individual tissue including effect of the hormones on carbohydrate metabolism as well as degradation of these hormones by these cells; b) to elucidate the mechanism of action of physiologic concentrations of ACTH by studying the nature of the second messenger responsible for steroidogenesis in the isolated adrenal cells.